In a service-delivery environment through Internet-centered public networks, values of all information are generally located on a server side rather than a client side.
Each client (terminal device) is basically a viewer, which browses information on the Internet. Each client issues various requests to obtain information from the Internet, which in return sends back information for the client. It means that all information is collected on the Internet, which offers formulaic information single-directionally. For this reason, it is difficult for manufacturers of client terminal devices to create added values for users.
In order to change this circumstance, the server-client relationship must be reversed by inverting the access direction. For a home network connected to the Internet, for example, an environment must be created such that access from the Internet to the home network is initiated, and services are provided by the home network to the Internet.
To achieve this, the internet network needs to be able to uniquely identify each device connected to the home network. Home routing and security problems need also to be resolved. One of the technologies to address this issue is IPv6 (Internet Protocol version 6).
However, in view of the circumstances regarding the current Japanese carriers and Internet service providers, it can be surmised that a considerable amount of time will have to be expended until the IPv6 becomes widely available. For example, it will take at least 2 to 3 years for the currently available IPv4 to depreciate, and the IPv6 service has just started on a test basis.
In order to achieve an IPv6-enabled network quickly, manufacturers will need to expand their business to include ISP level services, which is very costly and unrealistic. Furthermore, home network environments vary tremendously with their connection mechanisms varying widely depending on their carriers and ISP's. Therefore, a new, standardized approach is needed to realize the IPv6 environment by taking into account all these variations.
An example of prior art literature dealing with the above circumstances is JP-A-2001-274845. Although this prior art is cited herein, the novelty and inventive step of the invention according to the present application are not meant to be rendered moot.
When attempting to achieve the bi-directional access between the home network and the Internet using the IPv6 network in the conventional IPv4 environment, the following problems arise.
In the current IPv4 environment, for example, when installing a network home appliance at home, it has to be connected through the home network to a router connected to the Internet. In this case the IP address of the network home appliance becomes a private address and cannot be accessed from any network other than this particular home network.
Thus, conventionally, the access to a network home appliance has been achieved by employing a dedicated router capable of controlling the network home appliance, or by using a data center provided on the Internet to accumulate information for controlling the network home appliance and retrieving the information by polling from the network home appliance.
However, for the case of using the dedicated router, its versatility decreases and cost increases. For the case of retrieving the control information by polling, the access cannot be made real time, and the network and server load increases.
In view of the above circumstances, the objective of the present invention is to provide an Internet connection system capable of bi-directional communications between the home network and the Internet by relatively simple means, enabling manufacturers of client-side network home appliances to create added values for users.